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Subject: Re: [OMPI users] Open MPI vs IBM MPI performance help
From: Nysal Jan (jnysal_at_[hidden])
Date: 2010-12-03 06:31:36


Collecting MPI Profile information might help narrow down the issue. You
could use some of the tools mentioned here -
http://www.open-mpi.org/faq/?category=perftools

--Nysal

On Wed, Dec 1, 2010 at 11:59 PM, Price, Brian M (N-KCI) <
brian.m.price_at_[hidden]> wrote:

> OpenMPI version: 1.4.3
>
> Platform: IBM P5, 32 processors, 256 GB memory, Symmetric Multi-Threading
> (SMT) enabled
>
> Application: starts up 48 processes and does MPI using MPI_Barrier,
> MPI_Get, MPI_Put (lots of transfers, large amounts of data)
>
> Issue: When implemented using Open MPI vs. IBM’s MPI (‘poe’ from HPC
> Toolkit), the application runs 3-5 times slower.
>
> I suspect that IBM’s MPI implementation must take advantage of some
> knowledge that it has about data transfers that Open MPI is not taking
> advantage of.
>
> Any suggestions?
>
> Thanks,
>
> Brian Price
>
>
>
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